A maritime navigation display that provides visual feedback to improve conning officers' ship-handling during low visibility environments

Navigating a ship at night in close proximity to another vessel is a dangerous task. To improve conning officers' night time ship-handling performance, a visual navigation display is proposed that is mounted on the stern of the aircraft carrier that will help shipboard conning officers manoeuvre in a battle group formation. To test the effectiveness of the visual navigation display, the Nimitz-class aircraft and plane guard vessel, a Ticonderoga-class cruiser, were modelled in a virtual environment. A navigation display condition had significantly fewer navigational positional errors than a non-navigation display condition. The navigation display provided immediate feedback as to whether the aircraft carrier had changed bearing or speed, thus enabling the operator to initiate the appropriate input to maintain station astern of the carrier. Actual or potential applications of this research include the deployment of a maritime navigation display to assist conning officers' ship handling.     

A composite model for accurate colorimetric characterization of liquid crystal displays

This paper presents a composite color‐characterization model for Liquid Crystal Displays (LCDs), considering channel dependence and poor chromaticity constancy of primaries. The proposed model consists of two parts, that is, the Piecewise Linear assuming Variation in Chromaticity (PLVC) model and a partition compensation error model. PLVC model can accurately predict CIEXYZ for primaries and calculate the CIEXYZ of any digital input values ( d _r , d _g , d _b ) based on the channel independence assumption. In addition, the prediction error of PLVC model is compensated in RGB subspace using the partition compensation error model. The color difference Δ was used to evaluate the accuracy of the model. The result of this experiment shows that PLVC model performs well for LCDs with channel independence and poor chromaticity constancy of primaries, compared with other characterization models. For channel dependence and poor chromaticity constancy LCDs, our result shows that proposed composite color‐characterization model also has better prediction accuracy than all other tested models. In this study, measurements were conducted in ambient light environment, and the experiment results consist with practical applications.     

Under the weather: an evaluation of different modes of presenting meteorological information for pilots

Understanding current and forecast weather conditions for a planned route of flight is vital for general aviation (GA) pilots. Weather information can be obtained from multiple sources and in multiple formats, ranging from abbreviated code provided by aviation weather forecasters to animated graphical displays available on TV and the Internet. The present study investigated the effectiveness of graphical displays of meteorological information. A commercially available graphical display was ergonomically redesigned and the original and redesigned displays were compared with an ordinary text statement. Recall of information was significantly affected by display type. Comparisons showed the ergonomically redesigned display to be superior to the ordinary text statement. Performance was affected by participants’ general level of familiarity with evaluating data displays as measured by their area of study (sciences or humanities). The generalizability of the results to the pilot population is discussed.     

Latency impact on Quality of Experience in a virtual reality simulator for remote control of machines

In this article, we have investigated a VR simulator of a forestry crane used for loading logs onto a truck. We have mainly studied the Quality of Experience (QoE) aspects that may be relevant for task completion, and whether there are any discomfort related symptoms experienced during the task execution. QoE experiments were designed to capture the general subjective experience of using the simulator, and to study task performance. The focus was to study the effects of latency on the subjective experience, with regards to delays in the crane control interface. Subjective studies were performed with controlled delays added to the display update and hand controller (joystick) signals. The added delays ranged from 0 to 30 ms for the display update, and from 0 to 800 ms for the hand controller. We found a strong effect on latency in the display update and a significant negative effect for 800 ms added delay on latency in the hand controller (in total approx. 880 ms latency including the system delay). The Simulator Sickness Questionnaire (SSQ) gave significantly higher scores after the experiment compared to before the experiment, but a majority of the participants reported experiencing only minor symptoms. Some test subjects ceased the test before finishing due to their symptoms, particularly due to the added latency in the display update.     

双层衍射元件在投影式头盔光学系统设计中的应用

利用双层衍射元件设计了一款折衍混合投影式头盔光学系统。系统的衍射效率在可见光波段＞90%,提高了像面图像的对比度,增加了色彩真实性。在出瞳距离为25 mm,出瞳直径为10 mm条件下,系统的视场角为50°,有效焦距为32 mm,直径为19.2 mm,重量为7.8 g,继承了投影式头盔光学系统的轻小性特征;调制传递函数(MTF)在38 lp/mm时,边缘视场达到0.3以上,中心视场达到0.6,充分满足2.8 cm(1.1 in)彩色LCD微显示器的SXGA显示模式;系统垂轴色差为8.2 μm,场曲为0.4 m^-1,畸变为5%,成像质量满足虚拟环境和可视化训练要求。文中给出了双层衍射元件的二元面特征曲线,每周期刻蚀八个台阶时,最小特征尺寸为6.3 μm,且易于加工实现。     

Luminance and luminance contrast requirements for legibility of self-luminous displays in aircraft cockpits

A series of studies was conducted to investigate the effects of display background luminance, display contrast ratio and adaptation luminance on the legibility of self-luminous displays in aircraft cockpits. The studies were designed to avoid the typical confounding of these three variables, and employed luminance levels that are representative of operational conditions. The data show that with typical display symbols and luminances under low and moderate ambient illumination, contrast ratio is the major determinant of legibility; that increasing contrast ratios beyond as little as 1·4:1 may provide no significant improvements in legibility; and that, beyond their contribution to contrast ratio, the absolute luminances of the symbol and the background have no significant effect on legibility. Given the high ambient illumination typical of a sunny day, however, the pilot is adapted to luminances of up to 32 264 cd/m² (10 000 fL). Under these conditions, increases in contrast ratio of up to 30:1 are shown to improve legibility. When the adaptation luminance is more than 100 times that of the display background luminance, symbols on the display cannot be immediately identified, and the absolute luminances of the adapting field and the display background contribute to recovery time apart from their ratio relationship. Hyperbolic functions are applied to describe the multiplicative effects of these variables on legibility.     

Transparent electrodes based on conducting polymers for display applications

The materials science and engineering related to the fabrication of conducting polymer thin films and the progress in the development of devices integrated with organic transparent electrodes based on conducting polymers for display applications are reviewed. Transparent electrodes are essential components for many display modules. With the evolution of display technologies, conducting polymers are recently emerging as important alternative materials for the fabrication of transparent electrodes. Conducting polymers offer some advantages, such as light weight, low cost, mechanical flexibility and excellent compatibility with plastic substrates for the development of next-generation display technologies and, in particular, are expected to play an important role in the development of flexible display technologies.     

Monitoring dynamic processes with alphanumeric and graphic displays

Three experiments assessed the relative efficiency of graphic and tabular displays for detecting changes in periodic sine functions, simulating a dynamic process. In all three experiments, line graphs had an advantage over tables for response times, for correct detections and identifications, and for false alarms. However, this advantage depended on the type of change that indicated a malfunction. The largest difference between the displays was evident for the detection of changes in a function's frequency and smaller differences were found for the detection of changes in amplitude and intercept. Results also indicated that participants adapted their detection methods to the types of possible changes. The findings demonstrate the value of graphic displays for process control and substantiate the claim that graphic displays have an advantage when the displayed information has inherent structure and when the task requires the use of this structure. In addition, task performance was the subject of adaptive changes, which depend on the context in which the task is performed.     

No evidence for prolonged latency of saccadic eye movements due to intermittent light of a CRT computer screen

Despite previous studies it remains unclear, whether saccadic eye movements across computer screens may be adversely affected by the intermittency of light of cathode ray tubes (CRT). We measured the latency of simple saccades to peripheral targets presented on a CRT-screen, operated at refresh rates of 50, 100 and 150 Hz, compared with a special fluorescent lamp display (FLD). Our results suggest that the intermittent light of CRT screens does not prolong the latency of saccades not even relative to a control condition of unmodulated steady light at the FLD. Further, there was no evidence for any individual effect in possibly susceptible subjects, e.g. at high critical flicker frequencies (CFF).     

Minimizing distortions: seating requirements for stereo projection rooms

Stereoscopic information is distorted when the observer is not seated at the correct station point. Given a number of people who must watch a stereoscopic display simultaneously, what is the best seating arrangement so that as few people as possible will suffer from distorted perception? This question was analysed mathematically. Regardless of the configuration displayed, it is best to use as large a display as practical, seat viewers as far from the screen as possible in a small number of rows, and compute the station point accordingly. However, the distortion function varies greatly in shape and extent from one configuration to another. It is therefore impossible to give generally valid values for the tradeoff between distance and orientation: these depend on both the specific configuration and its orientation. Guidelines on how to compute the best seating arrangement in any given case are provided.